UNIT 4

GLOBAL NETWORK

4.1       World Web Wide

Definitions

The World Wide Web ("WWW" or simply the "Web") is a global information medium which users can read and write via computers connected to the Internet. The term is often mistakenly used as a synonym for the Internet itself, but the Web is a service that operates over the Internet, just as e-mail also does. The history of the Internet dates back significantly further than that of the World Wide Web.

History of the Web

Sir Tim Berners-Lee is a British computer scientist. He was born in London, and his parents were early computer scientists, working on one of the earliest computers.

Growing up, Sir Tim was interested in trains and had a model railway in his bedroom. He recalls:

“I made some electronic gadgets to control the trains. Then I ended up getting more interested in electronics than trains. Later on, when I was in college I made a computer out of an old television set.”

After graduating from Oxford University, Berners-Lee became a software engineer at CERN, the large particle physics laboratory near Geneva, Switzerland. Scientists come from all over the world to use its accelerators, but Sir Tim noticed that they were having difficulty sharing information.

“In those days, there was different information on different computers, but you had to log on to different computers to get at it. Also, sometimes you had to learn a different program on each computer. Often it was just easier to go and ask people when they were having coffee…”, Tim says.

Tim thought he saw a way to solve this problem – one that he could see could also have much broader applications. Already, millions of computers were being connected together through the fast-developing internet and Berners-Lee realised they could share information by exploiting an emerging technology called hypertext.

In March 1989, Tim laid out his vision for what would become the web in a document called “Information Management: A Proposal”. Believe it or not, Tim’s initial proposal was not immediately accepted. In fact, his boss at the time, Mike Sendall, noted the words “Vague but exciting” on the cover. The web was never an official CERN project, but Mike managed to give Tim time to work on it in September 1990. He began work using a NeXT computer, one of Steve Jobs’ early products.

By October of 1990, Tim had written the three fundamental technologies that remain the foundation of today’s web (and which you may have seen appear on parts of your web browser):

• HTML: HyperText Markup Language. The markup (formatting) language for the web.
• URI: Uniform Resource Identifier. A kind of “address” that is unique and used to identify to each resource on the web. It is also commonly called a URL.
• HTTP: Hypertext Transfer Protocol. Allows for the retrieval of linked resources from across the web.

4.2       The Internet is Global

The Internet is the global system of interconnected computer networks that use the Internet protocol suite (TCP/IP) to link billions of devices worldwide.

This statistic gives information on the total number of worldwide internet users from 2005 to 2015. As of the most recent reported period, the number of internet users worldwide was 3.17 billion, up from 2.94 billion in the previous year.

September 2, 1969: First time two computers communicated with each other. Oct 29, 1969: Message sent from computer to computer in different locations. Jan 1, 1983: ARPANET adopted the standard TCP/IP protocol. March 1989: Tim Berners-Lee invented the World Wide Web.

global network is any communication network which spans the entire Earth. The term, as used in this article refers in a more restricted way to bidirectional communication networks, and to technology-based networks.

4.3       Searching for Information on the Internet

How to find information on the Internet

Most information is found on the Internet by utilizing search engines. A search engine is a web service that uses web robots to query millions of pages on the Internet and creates an index of those web pages. Internet users can then use these services to find information on the Internet. When searching for information on the Internet, keep the below things in mind.

Surround searches in quotes

If you are searching for multiple common words, such as computer and help, it is a good idea to place quotes around the full search to get better results. For example, type "computer help" as your search criteria. This trick can also be used in parts of your search query. For example, Microsoft "computer help" would search for anything containing 'Microsoft' and that also has "computer help" together. Finally, you can also do multiple words surrounded in quotes. For example, "Microsoft Windows" and "computer help" would refine your results even more.

Be aware of stop words

Many search engines will strip out common words they refer to as stop words for each search that is performed. For example, instead of searching for why does my computer not boot, the search engine would search for computer and boot. To help prevent these stop words from being stripped out, surround the search with quotes.

Tip: If stop words are not important, don't enter them into your search.

Familiarize yourself with Booleans

Many search engines allow Booleans, which can help filter out bad results. Although common Booleans include "and", "or", and "not", most search engines have replaced these keywords with symbols. For example, to find computer help without results containing Linux, you would type computer help -linux. The "-linux" tells the search engine to exclude any results containing the word Linux.

Know what features are available

Many search engines allow for additional syntax to help limit your search strings. For example, Google enables users to search for links to a particular page by typing "link:" and other keywords at the beginning of the search query. For example, to see who is linked to Computer Hope, you'd type: link:http://www.computerhope.com.